Problem: The grades on a geometry midterm at Santa Rita are normally distributed with $\mu = 66$ and $\sigma = 5.0$. Brandon earned a $70$ on the exam. Find the z-score for Brandon's exam grade. Round to two decimal places.
Explanation: A z-score is defined as the number of standard deviations a specific point is away from the mean We can calculate the z-score for Brandon's exam grade by subtracting the mean $(\mu)$ from his grade and then dividing by the standard deviation $(\sigma)$ $ { z = \dfrac{x - {\mu}}{{\sigma}}} $ $ { z = \dfrac{70 - {66}}{{5.0}}} $ ${ z \approx 0.80}$ The z-score is $0.80$. In other words, Brandon's score was $0.80$ standard deviations above the mean.